When building a debugging kernel with modules, build modules with

debugging support as well.  Debugging module support is handled
identically to kernel debugging support, right down to poor
choice of make variable names.

sys/conf/Makefile.i386

@@ -272,6 +272,9 @@ MKMODULESENV=	MAKEOBJDIRPREFIX=${.OBJDIR}/modules KMODDIR=${KODIR}
 .if defined(MODULES_OVERRIDE)
 MKMODULESENV+=	MODULES_OVERRIDE="${MODULES_OVERRIDE}"
 .endif
+.if defined(DEBUG)
+MKMODULESENV+=	DEBUG="${DEBUG}" DEBUG_FLAGS="${DEBUG}"
+.endif
 
 modules:
 	@mkdir -p ${.OBJDIR}/modules

sys/conf/kmod.mk

@@ -77,6 +77,7 @@
 
 KMODLOAD?=	/sbin/kldload
 KMODUNLOAD?=	/sbin/kldunload
+OBJCOPY?=	objcopy
 
 TARGET_ARCH?=	${MACHINE_ARCH}
 
@@ -131,7 +132,15 @@ OBJS+=  ${SRCS:N*.h:R:S/$/.o/g}
 PROG=	${KMOD}.ko
 .endif
 
-${PROG}: ${KMOD}.kld
+.if !defined(DEBUG)
+FULLPROG=	${PROG}
+.else
+FULLPROG=	${PROG}.debug
+${PROG}: ${FULLPROG}
+	${OBJCOPY} --strip-debug ${FULLPROG} ${PROG}
+.endif
+
+${FULLPROG}: ${KMOD}.kld
 	${LD} -Bshareable ${LDFLAGS} -o ${.TARGET} ${KMOD}.kld
 
 ${KMOD}.kld: ${OBJS}
@@ -188,7 +197,7 @@ ${_ILINKS}:
 	${ECHO} ${.TARGET} "->" $$path ; \
 	ln -s $$path ${.TARGET}
 
-CLEANFILES+= ${PROG} ${KMOD}.kld ${OBJS} ${_ILINKS} symb.tmp tmp.o
+CLEANFILES+= ${PROG} ${FULLPROG} ${KMOD}.kld ${OBJS} ${_ILINKS} symb.tmp tmp.o
 
 .if !target(install)
 .if !target(beforeinstall)